Performing fault diagnostics for equipment typically involves taking direct measurements relating to operating characteristics of the equipment and analyzing the measured data to detect the presence of fault modes. For example, in the case of oil-immersed transformers, conventional fault detection methods involve direct measurement of dissolved gas concentration levels in the oil. Conventional fault detection methods that involve direct measurement of quantities, however, suffer from a number of drawbacks. For example, in the case of oil-immersed transformers, direct measurement of dissolved gas concentration levels is a cumbersome process that requires extracting the oil from the transformer and directly sampling the oil to obtain measurements. Technical solutions that address at least some of these drawbacks are described herein.